JP2013153024A - Electrolytic capacitor and manufacturing method of the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an electrolytic capacitor having a structure which holds a sufficient amount of an electrolytic solution without causing breakage and cracks and is advantageous in terms of electric capacity increase and miniaturization.SOLUTION: In an electrolytic capacitor, an anode foil 1 and a cathode foil 2 are wound in a longitudinal direction through a separator 3. The anode foil 1 and the cathode foil 2 respectively have roughened surfaces, and multiple first and second grooves D1, D2 are formed on both surfaces or one surface of at least one of the anode foil 1 and the cathode foil 2 by laser processing. The first grooves D1 have end parts D1a on long sides 1A, 2A of the anode foil 1 and the cathode foil 2. The second grooves D2 intersect with the multiple first grooves D1.

Description

  The present invention relates to an electrolytic capacitor and a manufacturing method thereof.

  Conventional electrolytic capacitors are disclosed in Patent Documents 1 and 2, for example. The electrolytic capacitors disclosed in these documents include a cylindrical capacitor element. The capacitor element is configured by winding an anode foil and a cathode foil through a separator. In the manufacturing process, the capacitor element is immersed in a driving electrolyte (hereinafter referred to as “electrolytic solution”). By impregnating this electrolytic solution with a capacitor element, the electrolytic solution is held between the anode foil and the cathode foil. Thereby, a capacitor | condenser element comes to have the electrical property as a capacitor | condenser.

  In the electrolytic capacitors disclosed in Patent Documents 1 and 2, a concave portion is formed by subjecting an electrode foil such as an anode foil and a cathode foil before winding to plastic deformation with a roller with a protrusion or the like. When the electrode foil having such a recess overlaps with the separator and is wound, a gap is formed between the recess and the separator or between the portion other than the protrusion formed on the opposite side of the recess and the separator. To do. That is, the electrolytic solution easily enters the gap between the electrode foil and the separator and easily impregnates the entire separator. As a result, a sufficient electrolytic solution is retained between the anode foil and the cathode foil.

JP-A-9-298057 JP 2006-186248 A

However, this type of electrolytic capacitor generally uses a so-called high-magnification foil or high-pressure foil, in which the surface of the electrode foil is highly roughened and enlarged in order to increase the capacitance. In this type of electrode foil, such as a high-magnification foil or a high-pressure foil, the remaining core portion is relatively thin.
Therefore, when the concave portion (convex portion) is formed in the electrode foil by plastic deformation as in the conventional case, residual stress is likely to be generated in the deformed portion, and there is a difficulty that tearing or cracking is likely to occur when the electrode foil is wound. there were.

Further, as shown in FIG. 1 and the like of Patent Document 2, in the concave portion formed by plastic deformation, the height of the convex portion formed on the opposite side of the concave portion is considerably larger than the thickness of the electrode foil. When the electrode foil having such a convex portion and the separator are wound, the outer diameter of the capacitor element is increased due to the bulkiness of the convex portion.
Therefore, the concave portion formed by plastic deformation is disadvantageous in reducing the size of the entire capacitor.

  The present invention has been made in view of the above points, and the object of the present invention is to hold a sufficient amount of electrolyte without incurring tears or cracks. It is an object of the present invention to provide an electrolytic capacitor that can have an advantageous structure in terms of downsizing. Moreover, it is providing the manufacturing method of such an electrolytic capacitor.

  The electrolytic capacitor according to the present invention is an electrolytic capacitor in which a long anode foil and a cathode foil are wound in a longitudinal direction via a separator, and each of the anode foil and the cathode foil is roughened. And a plurality of grooves are formed by laser processing on both surfaces or one surface of at least one of the anode foil and the cathode foil.

According to this configuration, a plurality of grooves by laser processing are interposed between the electrode foil (anode foil and cathode foil) and the separator. Thereby, when the electrolytic solution is immersed, the entire separator is easily impregnated with the electrolytic solution through these grooves. Therefore, according to the electrolytic capacitor according to the present invention, a sufficient electrolytic solution can be held between the anode foil and the cathode foil. Further, since the plurality of grooves are formed by laser processing, there is no portion such as a deformed portion, and residual stress due to plastic deformation or the like does not occur.
Therefore, according to the electrolytic capacitor of the present invention, there is no risk of tearing or cracking when winding the electrode foil.
For example, when a plurality of grooves are formed only outside the electrode foil in the wound state, the extension of the electrode foil in the winding direction is relaxed by these grooves. Thereby, the intensity | strength of electrode foil can be raised and it can make it strong with respect to winding stress.
Moreover, the electrode foil has a roughened surface, and the surface area thereof is enlarged. Therefore, according to the electrolytic capacitor according to the present invention, the capacitance can be increased. Moreover, the groove | channel by laser processing does not form the part protruded on the opposite side.
Therefore, the electrode foil and the separator can be wound in a smaller state in a state where the electrode foil and the separator are in close contact with each other. That is, the outer diameter of the capacitor element formed by winding the electrode foil and the separator can be reduced as much as possible, and the entire electrolytic capacitor including the capacitor element can be reduced in size.

  Further, in the electrolytic capacitor according to the present invention, the plurality of grooves in each of the anode foil and the cathode foil have a plurality of first ends having end portions on long sides along the longitudinal direction of the anode foil and the cathode foil. It is characterized by including a groove.

  According to this configuration, the electrolytic solution easily enters the end portions of the plurality of first grooves from the long sides of the anode foil and the cathode foil. Thereby, a sufficient amount of electrolyte can be guided to the whole separator through the first groove, and a sufficient amount of electrolyte can be held between the anode foil and the cathode foil.

  The electrolytic capacitor according to the present invention is characterized in that the plurality of grooves in each of the anode foil and the cathode foil include second grooves intersecting with the plurality of first grooves.

  According to this configuration, for example, the second groove can be disposed so as to face the central portion of the separator, and the electrolytic solution can be guided from the plurality of first grooves to the second groove. As a result, a more sufficient amount of electrolyte can be guided to the central portion of the separator through the first and second grooves, and a more sufficient amount of electrolyte can be retained.

  The method for manufacturing an electrolytic capacitor according to the present invention includes a step of roughening the surfaces of each of the long anode foil and the cathode foil, and a plurality of grooves formed by laser processing on the surfaces of the anode foil and the cathode foil. A step of forming, a step of winding the anode foil and the cathode foil in a longitudinal direction through a separator, and producing a capacitor element; and immersing the capacitor element in an electrolyte; and the anode foil and the cathode foil And a step of holding the electrolytic solution between the two.

According to this configuration, an electrode foil such as an anode foil or a cathode foil having a roughened surface can be formed, and the surface area of these electrode foils can be increased. A plurality of grooves can be formed between the electrode foil and the separator by laser processing. According to such laser processing, a deformed portion is not formed, and residual stress due to plastic deformation or the like does not occur. Moreover, according to laser processing, the part which protruded on the opposite side of the groove | channel is not formed.
Therefore, when the electrolytic solution is immersed, the entire separator can be easily impregnated with the electrolytic solution through these grooves. Therefore, according to the method for manufacturing an electrolytic capacitor according to the present invention, a sufficient electrolytic solution can be held without causing tearing or cracking, and a structure that is advantageous in terms of increasing the capacitance and reducing the capacitance. Can be produced.

  Further, in the method of manufacturing the electrolytic capacitor according to the present invention, in the step of forming the plurality of grooves in each of the anode foil and the cathode foil, the electrolytic capacitor manufacturing method ends at a long side along the longitudinal direction of the anode foil and the cathode foil. A plurality of first grooves having a portion are formed.

  According to this configuration, it is possible to easily infiltrate the electrolyte from the long side of the electrode foil to the ends of the plurality of first grooves when the electrolyte is immersed. As a result, a sufficient amount of electrolytic solution can be guided to the central portion of the separator through the first groove, and a sufficient amount of electrolytic solution can be held between the anode foil and the cathode foil.

  In the method for manufacturing an electrolytic capacitor according to the present invention, in the step of forming the plurality of grooves in each of the anode foil and the cathode foil, a second groove that intersects with the plurality of first grooves is formed. It is characterized by doing.

  According to this configuration, for example, the second groove can be formed in a region corresponding to the central portion of the separator, and the electrolytic solution can be guided from the plurality of first grooves to the second groove. As a result, a more sufficient amount of electrolyte can be guided to the central portion of the separator through the first and second grooves, and an even more sufficient amount of electrolyte can be held.

  According to the present invention, it is possible to provide an electrolytic capacitor that can hold a sufficient electrolytic solution without causing tearing or cracking, and that has an advantageous structure in terms of capacity increase and miniaturization. Can do. Moreover, the manufacturing method of such an electrolytic capacitor can be provided.

It is a perspective view which shows the capacitor | condenser element of the electrolytic capacitor which concerns on 1st Embodiment of this invention. It is sectional drawing which shows the structure of the electrolytic capacitor which concerns on 1st Embodiment of this invention. It is an expanded view which shows the state which expand | deployed the capacitor | condenser element shown in FIG. It is sectional drawing which shows the cross section of the groove | channel formed in the capacitor | condenser element shown in FIG. It is a flowchart which shows the manufacturing process of the electrolytic capacitor which concerns on 1st Embodiment of this invention. It is a perspective view for demonstrating the laser processing process shown in FIG. It is an expanded view which shows the state which expand | deployed the capacitor | condenser element of the electrolytic capacitor which concerns on 2nd Embodiment of this invention. It is an expanded view which shows the state which expand | deployed the capacitor | condenser element of the electrolytic capacitor which concerns on 3rd Embodiment of this invention. It is an expanded view which shows the state which expand | deployed the capacitor | condenser element of the electrolytic capacitor which concerns on 4th Embodiment of this invention. It is an expanded view which shows the state which expand | deployed the capacitor | condenser element of the electrolytic capacitor which concerns on 5th Embodiment of this invention. It is an expanded view which shows the state which expand | deployed the capacitor | condenser element of the electrolytic capacitor which concerns on 6th Embodiment of this invention. It is an expanded view which shows the state which expand | deployed the capacitor | condenser element of the electrolytic capacitor which concerns on 7th Embodiment of this invention. It is sectional drawing which shows the cross section of the groove | channel formed in the capacitor | condenser element as another example. It is sectional drawing which shows the cross section of the groove | channel formed in the capacitor | condenser element as another example.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

  FIG. 1 is a perspective view showing a capacitor element of an electrolytic capacitor according to a first embodiment of the present invention. FIG. 2 is a cross-sectional view showing the configuration of the electrolytic capacitor according to the first embodiment of the present invention. FIG. 3 is a development view showing a state where the capacitor element shown in FIG. 1 is developed. FIG. 4 is a cross-sectional view showing a cross section of a groove formed in the capacitor element shown in FIG.

  As shown in FIG. 1, the electrolytic capacitor has a long anode foil 1 and a cathode foil 2 that have been subjected to etching treatment, oxide film formation treatment, and laser processing treatment, with a separator 3 made of paper or synthetic fiber. The capacitor element 7 is configured to be wound in the longitudinal direction and fixed with the element stopper tape 6. In the following description, when the anode foil 1 and the cathode foil 2 are not particularly distinguished, the anode foil and the cathode foil are collectively referred to as “electrode foil”.

  As shown in FIG. 2, the capacitor element 7 is impregnated with an electrolytic solution and then accommodated in a bottomed cylindrical outer case 12.

A sealing body is attached to the opening of the outer case 12. This opening has a structure sealed by drawing. The sealing body is configured by bonding the elastic member 11 to the bakelite 10.
An element fixing agent 14 may be filled between the outer case 12 and the capacitor element 7 in order to fix the capacitor element 7 to the outer case 12.

  An anode terminal 8 and a cathode terminal 9 are formed on the outer end surface of the sealing body (bakelite 10 and elastic member 11). The lower ends of the anode terminal 8 and the cathode terminal 9 are electrically connected to the lead wires 4 ′ and 5 ′ of the anode lead lead 4 and the cathode lead lead 5 drawn out from the capacitor element 7 through welds 13 </ b> A and 13 </ b> B. ing.

  The anode lead 4 is subjected to chemical conversion treatment. In general, the cathode lead 5 is not subjected to chemical conversion treatment. Any of the lead leads (the anode lead lead 4 and the cathode lead lead 5) is generally made of a valve metal foil that has not been subjected to surface processing.

  The sealing of the substrate self-supporting type electrolytic capacitor is made by the elastic member 11 of the sealing body and the curled portion of the outer case 12.

  In the present embodiment, the electrode foils 1 and 2 have a highly roughened surface through an etching process described later, and are made of a so-called high-magnification foil or high-pressure foil. Thereby, the surface area of the electrode foils 1 and 2 is expanded from the apparent surface area. As the electrode foils 1 and 2, for example, aluminum foil is used.

As shown in FIG. 3, a plurality of grooves D1, D2 are formed on the surface of one side of the electrode foils 1, 2 by laser processing. The first groove D1 is formed such that both end portions D1a coincide with the long sides 1A and 2A along the longitudinal direction of the electrode foils 1 and 2, respectively.
The plurality of first grooves D1 are arranged at predetermined intervals in the longitudinal direction of the electrode foils 1 and 2, and are formed along the width direction thereof. A plurality of second grooves D2 are arranged at predetermined intervals in the width direction of the electrode foils 1 and 2, and are formed along the longitudinal direction thereof. Thereby, the second groove D2 is formed in a region facing the central portion of the separator 3, and intersects the plurality of first grooves D1.

As shown in FIG. 4, the first and second grooves D1 and D2 formed by laser processing have a V-shaped concave cross section. The width of the first and second grooves D1, D2 is about 0.1 to 5.0 mm. The depths of the first and second grooves D1 and D2 are 10 μm or more and about the thickness of the oxide film described later.
The electrode foils 1 and 2 according to the present embodiment have the first and second grooves D1 and D2 formed only on the outer surface, but the first and second grooves D1 and D2 are formed only on the inner side. The same effect can be obtained with respect to the retention of the electrolytic solution even when the first and second grooves D1 and D2 are formed on both the outer and inner surfaces.

  Next, a method for manufacturing the electrolytic capacitor according to the first embodiment will be described. FIG. 5 is a flowchart showing manufacturing steps of the electrolytic capacitor according to this embodiment. FIG. 6 is a perspective view for explaining the laser processing shown in FIG.

(Etching process)
First, in the etching step, an aluminum foil is placed in an etching solution (strongly acidic aqueous solution such as hydrochloric acid), and an electrochemical treatment (etching treatment) is performed on the aluminum foil with a DC voltage or an AC voltage. Thereby, the surface of the aluminum foil is roughened and roughened, and the surface area is increased. Thereby, electrode foils 1 and 2 such as a high-magnification foil or a high-pressure foil are formed (step S101).

(Chemical conversion process)
Next, in the chemical conversion step, the electrode foils 1 and 2 are placed in a chemical conversion solution (weakly acidic aqueous solution such as ammonium borate), and a DC voltage is applied to the electrode foils 1 and 2. Thereby, an aluminum oxide film serving as a dielectric is formed on the surfaces of the electrode foils 1 and 2 (step S102).

(Laser processing process)
The capacitor element 7 first forms a core while winding the separator 3, and inserts the anode foil 1 and the cathode foil 2 between the core and the separator 3 that is subsequently wound up, from the core side. The separator 3, the cathode foil 2, the separator 3, and the anode foil 1 are wound in a cylindrical shape so as to be in this order.
In the laser processing step, laser irradiators L1 and L2 are disposed on the outer surfaces of the anode foil 1 and the cathode foil 2, respectively, and laser is directed from the laser irradiators L1 and L2 toward the surfaces of the anode foil 1 and the cathode foil 2. (See step S103, FIG. 6).
Thus, first and second grooves D1 and D2 as shown in FIGS. 3 and 4 are formed on the surfaces of the anode foil 1 and the cathode foil 2. In particular, the first groove D <b> 1 is formed by irradiating the laser while scanning in a direction intersecting the transport direction of the anode foil 1 and the cathode foil 2. Thus, both end portions D1a of the first groove D1 are formed so as to coincide with the long sides 1A and 2A of the anode foil 1 and the cathode foil 2.
The laser irradiation conditions are, for example, that the laser power is 10 to 70% of the maximum output, the scanning speed is 1000 to 2000 mm / s, the pulse period is 10 to 30 μs, and the irradiation time is 0.16 to 0.25 s (step S103). ). Note that various forms of grooves shown in other embodiments described later can be formed by changing the laser irradiation conditions and the scanning direction.
In addition, the separator 3 and the electrode foils 1 and 2 are separated from each other, and the laser irradiators L1 and L2 are disposed on both sides of the electrode foils 1 and 2, respectively. The first and second grooves D1 and D2 can also be formed on the surface.

(Casting and winding process)
In the caulking step, the lead materials 4 and 5 are connected by caulking or the like to the anode foil 1 and the cathode foil 2 in which the grooves D1 and D2 are formed by laser processing.
In the winding process, the grooves D1 and D2 are formed by laser processing, and the anode foil 1 and the cathode foil 2 to which the lead materials 4 and 5 are connected are inserted between the separators 3 and wound up. Stop with the stop tape (step S104).
In the present embodiment, after the laser processing step, the caulking / winding step is continuously performed. However, the laser processing step may be performed independently of the caulking / winding step.

(Impregnation process)
Next, in the impregnation step, the capacitor element 7 is impregnated with an electrolytic solution by reduced pressure, pressurization, or the like. The electrolyte enters both ends D1a of the first groove D1 from the long sides 1A and 2A of the electrode foils 1 and 2 and permeates into the first groove D1 by capillary action. Further, the electrolytic solution penetrates into the second groove D2 that intersects the first groove D1. That is, the electrolytic solution is sufficiently guided to the central portion of the separator 3 through the first and second grooves D1 and D2. Thus, the entire separator 3 is impregnated with the electrolytic solution, and a sufficient electrolytic solution is held between the anode foil 1 and the cathode foil 2.
The impregnation time at this time varies depending on the size of the capacitor element 7 and the type of the electrolytic solution. In general, the larger the element size, the longer the impregnation time and the lead time. However, the impregnation time propagates through the first and second grooves D1 and D2. Therefore, the lead time is shorter than that without the groove. Further, at the time of decompression, the air contained in the capacitor element 7 is smoothly discharged through the first and second grooves D1 and D2, so that the decompression time can be shortened. (Step S105).
After the impregnation step, a certain amount of excess electrolyte is removed by a centrifuge.

(Assembly process)
Next, in the assembly process, the capacitor element 7 impregnated with the electrolytic solution and the sealing body (the bakelite 10 and the elastic member 11) are joined, and then accommodated in the outer case 12, and as shown in FIG. The element fixing member 14 is filled in the outer peripheral surface of the lower end portion of the element 7, and the opening of the outer case 12 is further sealed (step S106). Thereby, a semi-finished product of the electrolytic capacitor is formed.

(Aging process)
Next, in the aging process, a DC voltage is applied to the electrolytic capacitor at a high temperature to repair the oxide film damaged by the laser processing or winding of the electrode foils 1 and 2 (step S107). Thereby, a finished product of the electrolytic capacitor is formed.

  According to the electrolytic capacitor having the above configuration and the manufacturing method thereof, the following effects can be obtained.

Between the electrode foils 1 and 2 and the separator 3, elongated first and second grooves D1 and D2 are formed by laser processing, and the electrolytic solution travels through the first and second grooves D1 and D2. The center part of the separator 3 is easily impregnated.
As a result, the entire separator 3 can be impregnated with the electrolytic solution, and a sufficient amount of electrolytic solution can be held between the anode foil 1 and the cathode foil 2.

Since the first and second grooves D1 and D2 are formed by fine cutting by laser processing, there is no portion that is formed by plastic deformation, and no residual stress is generated in the electrode foils 1 and 2. . Thereby, even when the electrode foils 1 and 2 such as a high-magnification foil and a high-pressure foil are wound, there is no possibility of causing a tear or a crack.
Further, at the time of winding, the outer sides of the electrode foils 1 and 2 are pulled more than the inner side to increase the elongation rate, but the elongation is alleviated by the first groove D1 formed on the outer surface. . Thereby, the intensity | strength of the electrode foils 1 and 2 at the time of winding can be raised, and it can make it strong with respect to winding stress.

  Since the electrode foils 1 and 2 have a roughened surface, their surface areas are considerably larger than the apparent surface area. As a result, the capacitance of the electrolytic capacitor can be increased.

Since the first and second grooves D1 and D2 are formed by laser processing, a portion protruding to the opposite side is not formed. Thereby, it can wind more small in the state which contacted the separator 3 over the whole surface of electrode foil 1,2.
That is, the outer diameter of the capacitor element 7 formed by winding the electrode foils 1 and 2 and the separator 3 is made as small as possible, and the entire electrolytic capacitor is miniaturized together with the outer case 12 that accommodates the capacitor element 7. Can do.

  Next, a capacitor element of an electrolytic capacitor according to another embodiment will be described. Note that the same or similar components as those according to the first embodiment described above are denoted by the same reference numerals and description thereof is omitted.

  FIGS. 7-12 is an expanded view which shows the state which expand | deployed the capacitor | condenser element of the electrolytic capacitor based on other embodiment of this invention. 13 and 14 are cross-sectional views showing a cross section of a groove formed in a capacitor element as another example.

  As shown in FIG. 7, in the capacitor element 7 of the second embodiment, only one second groove D <b> 2 is formed in the central portion of the electrode foils 1 and 2 facing the central portion of the separator 3. Even with such a configuration, it is possible to easily impregnate the electrolytic solution to the central portion of the separator 3 through the second groove D2, and a sufficient electrolytic solution is held between the anode foil 1 and the cathode foil 2. be able to.

As shown in FIG. 8, in the capacitor element 7 of the third embodiment, only one second groove D2 is formed as in the second embodiment, and one end of the first groove D1 is formed. Only D1a is formed so as to coincide with the long sides 1A and 2A of the electrode foils 1 and 2.
The plurality of first grooves D1 are formed on both sides of the second groove D2 as a center, and are arranged so as to be staggered along the longitudinal direction of the electrode foils 1 and 2. As a result, the other end of the first groove D1 intersects the second groove D2. Even with such a configuration, the electrolytic solution can be guided from the first groove D1 to the second groove D2.

  As shown in FIG. 9, in the capacitor element 7 of the fourth embodiment, the first grooves D1 are formed obliquely with respect to the longitudinal direction of the electrode foils 1 and 2 so as to intersect each other. The second groove is not provided. According to such a configuration, the driving electrolyte can be guided to the central portion of the separator 3 only through the first groove D1.

  As shown in FIG. 10, the capacitor element 7 of the fifth embodiment is equivalent to the capacitor element 7 of the first embodiment in which the second groove is not provided. Even with such a configuration, the electrolytic solution can be guided to the central portion of the separator 3 only through the first groove D1.

  As shown in FIG. 11, in the capacitor element 7 of the sixth embodiment, the first grooves D1 are formed obliquely with respect to the longitudinal direction of the electrode foils 1 and 2 so as to be parallel without crossing each other. ing. Even with such a configuration, the electrolytic solution can be guided to the central portion of the separator 3 only through the first groove D1.

  As shown in FIG. 12, in the capacitor element 7 of the seventh embodiment, the first groove D1 is formed in a meandering curve between the long sides 1A, 2A on both sides of the electrode foils 1, 2. The end D1a of the first groove D1 is formed so as to always coincide with the long sides 1A and 2A on both sides of the electrode foils 1 and 2. As a result, a plurality of first grooves D1 are formed so as to be interrupted at the long sides 1A, 2A of the electrode foils 1, 2. Even with such a configuration, the electrolytic solution can be guided to the central portion of the separator 3 only through the first groove D1.

  As shown in FIGS. 13 and 14, the first and second grooves D1 and D2 may have a concave or semicircular cross section. In addition, although not particularly illustrated, the cross sections of the first and second grooves D1 and D2 may be U-shaped or trapezoidal. Such cross sections of the first and second grooves D1, D2 can be formed by appropriately changing the laser irradiation conditions described above.

  In addition, this invention is not limited to the structure by each above-mentioned embodiment.

For example, the first groove or the second groove may be formed such that the inner groove is located closer to the inner side than the outer side of the capacitor element, or vice versa. In such a case, it is possible to suitably cope with the case where the impregnation property of the electrolytic solution is different between the outside and the inside of the capacitor element.
Specifically, the lower the impregnation property, the narrower the gap between the grooves and the denser the grooves, the higher the electrolyte impregnation property.

DESCRIPTION OF SYMBOLS 1 Anode foil 1A Long side 2 Cathode foil 2A Long side 3 Separator 4, 5 Lead material D1 1st groove | channel D1a End part D2 2nd groove | channel

Claims (6)

An electrolytic capacitor in which a long anode foil and a cathode foil are wound in a longitudinal direction via a separator,
Each of the anode foil and the cathode foil has a roughened surface, and at least one of the anode foil and the cathode foil has a plurality of grooves formed on both sides or one side by laser processing. An electrolytic capacitor characterized by that.   The plurality of grooves in each of the anode foil and the cathode foil includes a plurality of first grooves having ends on long sides along the longitudinal direction of the anode foil and the cathode foil. Item 2. The electrolytic capacitor according to Item 1.   The electrolytic capacitor according to claim 2, wherein the plurality of grooves in each of the anode foil and the cathode foil includes a second groove that intersects the plurality of first grooves. A step of roughening the surface of each of the long anode foil and the cathode foil;
Forming a plurality of grooves by laser processing on the surface of each of the anode foil and the cathode foil;
Winding the anode foil and the cathode foil in a longitudinal direction through a separator, and producing a capacitor element;
Immersing the capacitor element in an electrolytic solution, and holding the electrolytic solution between the anode foil and the cathode foil;
The manufacturing method of the electrolytic capacitor characterized by including these.   In the step of forming the plurality of grooves in each of the anode foil and the cathode foil, a plurality of first grooves having ends on the long sides along the longitudinal direction of the anode foil and the cathode foil are formed. The manufacturing method of the electrolytic capacitor of Claim 4 characterized by these.   6. The step of forming the plurality of grooves in each of the anode foil and the cathode foil forms a second groove that intersects with the plurality of first grooves. Manufacturing method of electrolytic capacitor.

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